The present invention generally relates to memory devices and, in particular, to a memory element and method utilizing ion positioning to control the state of a memory element.
A memory element is a structure that stores at least one bit of information. Usually, a plurality of memory elements are programmed (i.e., are set to certain logical states) to define a digital word. Each memory element corresponds to one bit of the digital word and is set to a particular logic state depending on whether the corresponding bit is to be high or low. A detector can determine the value of the digital word by analyzing the states exhibited by the memory elements defining the digital word. In general, the use of memory elements to define digital words is well known in the art.
Many conventional memory elements require a relatively large number of components and/or processing steps to manufacture, thereby increasing the overall cost of producing the memory elements. Thus, a heretofore unaddressed need exists in the industry for an inexpensive memory element requiring a relatively small number of processing steps and/or components to manufacture.
The present invention overcomes the inadequacies and deficiencies of the prior art as discussed herein. The present invention relates to a simple and inexpensive memory element for storing a bit of data.
The memory element of the present invention utilizes a substrate, a first conductive connection, a second conductive connection, and an ionic layer. The substrate includes a source region, a drain region, and a channel region, which is disposed between the source region and the drain region. The ionic layer includes ions and is coupled to the substrate. The first connection is coupled to the source region, and the second connection is coupled to the drain region. An electrical field is applied through the ionic layer such that the ions in the ionic layer move.
When the memory element is to exhibit a logical high state (i.e., a xe2x80x9c1xe2x80x9d state), the polarity of the electrical field causes the ions to accumulate close to the channel region. This pulls electrons from the source and drain regions into the channel region, making the channel region conductive. When the memory element is to exhibit a logical low state (i.e., a xe2x80x9c0xe2x80x9d state), the polarity of the electrical field causes the ions to move away from the channel region. As a result, the channel region becomes non-conductive, and the first conductive connection is, therefore, insulated from the second conductive connection.
In accordance with another feature of the present invention, a controller may be used to manipulate the voltage of a metallic element and the substrate to control the positioning of the ions in the ionic layer. Therefore, the controller may be used to control whether the memory element exhibits a logical high or a logical low state.
In accordance with another feature of the present invention, the ionic layer is comprised of TEOS (tetraethyl orthosilicate) material. TEOS is a material that forms ions when heated to temperatures above approximately 800 degrees Celsius. For best results, the TEOS material is plasma deposited and is doped with boron or phosphorus.
The present invention can also be viewed as providing a method for storing information in memory. Briefly described, the method can be broadly conceptualized by the following steps: providing a substrate; forming a source region and a drain region in the substrate; forming a layer on the substrate; forming ions in the layer; controlling conductivity in a channel region of the substrate that is between the source region and the drain region by the electrical field; and moving the ions in response to the electrical field.
The present invention has many advantages, a few of which are delineated hereafter, as mere examples.
An advantage of the present invention is that a memory element can be easily and inexpensively manufactured.
Another advantage of the present invention is that a stable memory element can be created. Therefore, once the state of the memory element is established, further inputs are not needed to ensure that the state of the memory does not switch. As a result, the voltages applied to the memory element to program the state of the memory element may be turned off or removed after programming.
Other features and advantages of the present invention will become apparent to one skilled in the art upon examination of the following detailed description, when read in conjunction with the accompanying drawings. It is intended that all such features and advantages be included herein within the scope of the present invention, as is defined by the claims.